1. Field of the Invention
The present invention relates generally to authentication of transmissions based on scanned or digitized images, and relates more particularly to authentication of facsimile transmitted information in the form of an image.
2. Description of Related Art
Authentication of transmission and electronic communications is an important issue that has been addressed in a number of ways in various applications. For example, encryption is often used in computer networks to provide an authentication technique where it is believed that only the sender and receiver are able to access the content of a given communication. The sender encrypts the communication, for example, with a key that is part of a public/private key pair, and sends the encrypted information to the receiver over a communication link. The receiver decrypts the communication using the other part of the public/private key pair, and reviews the transmitted content. Sometimes an authentication code or element is transmitted with the communication, such as a checksum or time and date stamp. The code contributes to identifying the source and assuring the receiver that the received communication is authentic and the same as that transmitted by the sender.
Security for electronic images is also an important issue that may involve authentication with regard to unauthorized copying. Typically, an electronic image is “watermarked” to provide a secure indication of information associated with the image. Such associated information can include the author, owner, time and date created, particular characteristics related to the image and so forth. The watermark is not visible as part of the image, but is in the form of an electronic signature typically embedded in the data of the file containing the image. The watermarked image is static, in that it does not reflect any information associated with a transmission process. Typically, an image watermark is used to secure intellectual property rights in the image, or provide evidentiary support for claims of authorship, ownership and the like.
Authentication may also be an issue involved in the comparison of two electronic copies of a document, for example. Typically, the electronic documents are compared on a unit-by-unit basis, such as byte by byte or word for word. This type of comparison and authentication typically assumes the two documents are in the same format and are generated by the same program or software. That is, the authentication is conducted based on direct electronic comparisons between the documents. This type of comparison or authentication is specific to a particular format of document and does not relate to image inspection or authentication. In addition, this type of document authentication does not take into account transmission of documents and their authentication over a communication link. Moreover, this type of document comparison does not operate directly on hard copy image files, such as scanned documents or images in electronic format.